JP2011519399A - Honeycomb body and method for producing brazed honeycomb body - Google Patents

Abstract

A honeycomb body (1) having at least one housing (2) and a metal foil (3) forming a duct structure (4) is provided, the duct structure (4) comprising a number of linear soldered connections. It is fastened to the housing (2) by (5). The present invention also proposes a manufacturing method used to provide these linear soldered connections (5) between the duct structure (4) and the housing (2). Such a honeycomb body is particularly used as an exhaust gas purification device in an exhaust system of an internal combustion engine of a vehicle.
[Selection] Figure 4

Description

  The present invention relates to a honeycomb body having at least one housing and a metal foil forming a channel structure. Such a honeycomb body is particularly used as an exhaust gas purification device in an exhaust system of an internal combustion engine of a vehicle.

  This type of honeycomb body is usually from single and / or multi-part housings with a relatively thick material thickness so that the housing can constitute the outline, shape and / or part of the exhaust line itself. It is configured. In contrast, in order to utilize as large a surface as possible in the same installation space, an effort is made to surround the metal foil for forming the channel structure relatively thinly. This surface is used, for example, for application to a catalyst in contact with exhaust gas flowing through a channel structure. This ensures an intensive contact between the exhaust gas components and the catalyst, and thus an effective purification of the exhaust gas.

  The problem here is that when alternating thermal and / or dynamic loads are always applied to the mobile exhaust system, the thin metal foil behaves differently compared to the relatively thick enclosed housing. It is to be. For this reason, the connection between the housing and the metal foil has a special technical problem.

  A piece of brazed material or so-called brazing foil is applied to the inner lateral surface in the housing of such a honeycomb body before integrating the metal foil, i.e. the channel structure, and then its It is known to insert into a channel structure. It is also known that such a brazing foil is wrapped around the channel structure and then this assembly is introduced into the housing and the entire brazing foil is pressed against the inner lateral surface of the housing. Similar methods have already been proposed, where the brazed area is not provided as a band over the entire circumference, but rather as a relatively large patch. The corresponding honeycomb body is shown in schematic form in FIG.

  This joining technique or application of brazing material is not used even if a large amount of brazing material is provided on the inner side surface of the housing, thus increasing the demand for the material, resulting in higher manufacturing costs and Not only can the braze material concentrate on the surface of the housing or metal foil, which can result in unwanted diffusion in the alloy elements of the housing and / or metal foil. Furthermore, it should be noted that this only achieves a limited adaptation of the brazing area to the thermal expansion and / or dynamic expansion behavior of the housing and / or metal foil.

  The object of the present invention is to at least partially solve the problems described with respect to the prior art. In particular, a honeycomb body is disclosed that exhibits improved durability against alternating thermal and / or dynamic loading of the honeycomb body in an exhaust system of a mobile internal combustion engine. The aim is also to disclose a manufacturing method that consumes the brazing material more economically.

  These objects are achieved using a honeycomb body according to the features of claim 1 of the claims and a method for manufacturing a honeycomb body according to claim 8 of the claims. Further preferred features of the honeycomb body or its manufacturing method and preferred use of the honeycomb body are disclosed in the claims which are organized as subordinates. It should be noted that the features disclosed in the claims may be combined with each other in any desired technically appropriate manner and may suggest further features of the invention. This description, in particular with reference to the drawings, further describes the present invention and discloses further variations of the embodiments.

  The honeycomb body according to the present invention has at least one housing and a metal foil that forms a channel structure, and the channel structure is attached to the housing by a plurality of linear brazed joints.

  The housing is preferably a single part and may have a cylindrical cross-sectional shape or a cross-sectional shape different from a circular shape. The metal foil preferably comprises an at least partially structured metal foil, the structured metal foil having a plurality of channels substantially parallel to each other, for example in the form of a honeycomb structure. It is at least rolled, coated and / or wound to form a channel structure. While the housing has a material thickness greater than 1 mm, the metal foil is embodied with a material thickness in the range of, for example, less than 0.12 mm, such as less than 0.08 mm.

  It is then proposed to provide a plurality of linear braze connections instead of using a known large braze area. Multiple here means in particular at least 10 brazing connections, for example more than 30 or at least 100 brazing connections. The linear embodiment of the brazing connection is preferably here oriented so that the embodiment is arranged transverse to the circumferential direction of the housing. In particular, the linear connection is parallel to the direction of the extent of the metal foil in the housing. A brazed connection is particularly “linear” if it is substantially longer than it is wide, in which case its width is determined in the direction of the circumference of the housing. “Linear” is particularly preferably narrower than, for example, the longest channel width of the channel structure. Therefore, it is clear that with these small multiple linear brazed connections, a more selective connection to the housing of the metal foil or channel structure, for example, places more load on the channel structure. It is possible for the location of the area, where it is possible to provide more linear brazed connections than other parts of the area, if necessary, or require relatively great flexibility A smaller number of linear brazed connections can be provided at these locations. In any case, the multiple brazed connections in this linear shape allow for flexible brazing pattern embodiments between the housing and the channel structure.

  In this connection, each of the linear brazing connections is preferably embodied with a width of up to 5 millimeters in the circumferential direction of the housing. This width preferably does not exceed a value of 3 mm or 1 mm. This application of brazing material that allows savings makes manufacturing more cost effective and prevents unwanted brazing connections in adjacent areas.

  Furthermore, it is advantageously envisaged that the plurality of metal foils are arranged such that they are in contact with the housing at least one edge and each form at least one linear brazed connection. The In other words, this means that the metal foil is moved so that it touches the inner lateral surface of the housing at the two edges of the metal foil, for example by winding, wrapping and / or overlapping the metal foil as appropriate. Means that These edges then touch this internal lateral surface of the housing or fit closely in the tangential direction to the housing. As a result of this shape and / or arrangement of the metal foil, a contact area with the housing and / or a preload where the edge is pressed against the housing can be set. For such a linear brazing joint, it is proposed to use exactly these contact areas or the areas of the edges of the metal foil that closely fit to these contact areas. As a result, the linear braze connection is, for example, precisely limited by the edges of the metal foil and extends from there to the interior region of each metal foil.

  According to one development, it is proposed that the housing has a brazing material in the contact area with the metal foil. This means in other words, for example, that, as a result of providing a conventional brazing piece, no brazing material distributed over the circumference of the housing remains between them. As a result, also in this area, only the actual contact area is provided with brazing material, so that the use of brazing material can be further reduced.

  According to another embodiment of the invention, a continuous brazing area on the circumference is not provided in the direction of the circumference of the housing. This is also intended to be substantially characterized in that the brazed area on the circumference is not on the inner circumference of the housing after the brazed honeycomb body has been manufactured. For the situation described here, this applies to the entire honeycomb body, ie the entire inner lateral surface of the housing covered by the channel structure.

  In addition, a circumferential brazing region having a plurality of linear brazing connections spaced apart from each other and perpendicular to the circumferential direction is advantageously provided in the circumferential direction of the housing. It is assumed that Such a brazing region has, for example, at least 20 linear brazing connections in the circumferential direction that are particularly aligned with one another in the circumferential direction and in particular parallel to one another. If desired, a plurality of such circumferential brazing regions may be provided, particularly close to the front side of the channel structure. However, in such a brazing region, the proportion of the surface area created by the linear brazing joints on the inner lateral surface in this circumferential brazing region is generally up to 50%, in particular up to 20%. , And more preferably still up to 10%.

  According to one development of the invention, a honeycomb body is proposed in which up to 10% of the surface area of the inner side area of the housing covered by the channel structure is embodied with linear brazed connections. This ratio is very preferably further up to 5% or even up to 2%. The inner lateral surface of the housing is, in other words, the surface covered by the channel structure, where the latter surface is generally axially bounded by the front side of the channel structure and is an intermediate circle A peripheral region is defined. As a result, it has the linearly shaped brazed joint proposed here, and in fact only a small part of its surface area can be coupled by the channel structure or the coupling technique between the metal foil and the housing. Form.

According to a further aspect of the invention, a method for manufacturing a honeycomb body is proposed, wherein the honeycomb body has at least one housing and a metal foil forming a channel structure. This method here includes at least the following steps.
(A) providing a plurality of metal foils;
(B) a step of arranging a plurality of adhesive pieces on at least a part of the metal foil;
(C) introducing a metal foil into the housing such that a channel structure is formed and at least a portion of the adhesive strip contacts the housing;
(D) brazing the honeycomb body such that the brazing material is disposed on the adhesive strip on the housing;
(E) A step of heating the honeycomb body to form a plurality of linear brazed joints between the metal foil and the housing.

  This method is particularly useful for producing the above-mentioned honeycomb bodies according to the invention.

  Step (a) particularly relates to the step of providing an at least partially structured metal foil, and more particularly preferably to providing a plurality of smooth metal foils and a plurality of corrugated metal foils.

  The step (b) relates to a step of applying the adhesive particularly to a predetermined region of the metal foil. What is highly preferred here is, inter alia, for the connection between the metal foil and the housing, these adhesive strips are arranged in the border region of the edge or in the contact region of the housing and edge. Preferably, the printing technique is applied in particular to applying an adhesive using a printing device (for example in an ink jet method). With such a printing device, it is possible to produce, for example, an adhesive strip, particularly precisely and in a controlled size, which also has, for example, the final linear shape of the brazing joint Corresponding to

  In step (c), the metal foil is then introduced (at least partially) into the housing. The metal foils can be pre-stacked (layered), stacked and / or wound and / or rolled for this purpose. This introduction to the housing can be carried out so that the metal foil is pushed (partially as required) into the housing (for example consisting of a single part), however, the metal foil (separated or opened) It is also possible to insert the housing and then close the housing. In any case, it is preferred that a channel structure is formed here which is substantially parallel to the direction of expansion of the housing. The metal foil is introduced at the same time so that at least a part of the adhesive strips, in particular the adhesive strips not connecting the metal foils to each other, are in contact with or directly in contact with the housing.

  Step (d) relates in particular to a method step in which the brazing material is arranged in contact with the adhesive strip from the front side of the honeycomb body over the channel structure. The brazing material, in particular the powdered brazing material, then sticks to the adhesive strip, and the desired amount of the brazing material is then actually fixed in the following steps.

  Step (e) then constitutes the thermal bonding method. It is preferred here that the honeycomb body is brazed at a high temperature, that is, if necessary, soldered at a temperature of, for example, 800 ° C. or higher under a defined ambient environment (vacuum or protective gas). This leads to a situation where the adhesive (binder) is substantially vaporized and the brazing material is liquefied. After heating, the brazing material is finally cooled, resulting in a material-locking connection of the metal foil, brazing material, and housing.

  Particularly preferably, the housing is provided without the use of adhesives and brazing materials. This applies in particular to step (e), except for the adhesive or brazing material which is transferred from the metal foil to the housing by step (c) or (d). In this connection, the housing can be used, for example, with passivating means to prevent unnecessary accumulation of adhesive and / or brazing material in other areas than those determined by the metal foil. It is very particularly preferred that it is provided on the side surface.

  Such a honeycomb body manufactured according to the invention and / or constructed according to the invention is particularly preferably used as an exhaust treatment element in an exhaust system of a vehicle.

  The present invention and the technical field will be described in more detail with reference to the drawings. It should be noted that the drawings are schematic and in particular show variations of preferred embodiments of the invention, but the invention is not limited thereto.

FIG. 1 shows the basic design of the exhaust system. FIG. 2 shows a cross section over the honeycomb body. FIG. 3 shows the brazing area between the housing and the metal foil according to the prior art. FIG. 4 shows a modification of an embodiment of the honeycomb body according to the present invention. FIG. 5 shows a variant of the preferred embodiment of the method according to the invention. FIG. 6 shows a variant of the preferred embodiment of the method according to the invention. FIG. 7 shows a variant of the preferred embodiment of the method according to the invention. FIG. 8 shows a variant of the preferred embodiment of the method according to the invention. FIG. 9 shows a variant of the preferred embodiment of the method according to the invention. FIG. 10 shows a variant of the preferred embodiment of the method according to the invention. FIG. 11 shows a possible embodiment of a structured metal foil for producing a honeycomb body. FIG. 12 shows details of a smooth metal foil with a linear braze connection.

  FIG. 1 is a schematic view of a vehicle 17 such as a passenger car or a truck. The vehicle 17 has an engine 18, for example a diesel engine or a spark ignition engine. The exhaust gas produced in the engine 18 flows through the exhaust system 16, which is typically embodied as an exhaust line and a plurality of exhaust treatment elements 15. The exhaust gas treatment elements used are in particular catalyst carrier bodies, filters, separators, adsorbers, plasma reactors, reformers and the like. It is here schematically shown that the exhaust gas treatment element 15 has a honeycomb body 1.

  FIG. 2 shows an embodiment of the honeycomb body 1 in a longitudinal section. Shown here on the outside is a housing 2 (having a relatively thick wall) made up of a single part and having a cylindrical shape. Inside this housing 2, the housing 2 forms a contact area 9, and the channel structure 4 is arranged inside the contact area 9. This channel structure 4 is formed of a plurality of smooth and structured metal foils 3. The channels 23 are formed here, and the channel extending directions 26 of these channels are substantially parallel to the axis 19 of the honeycomb body. Part of the walls of the channel structure 4 can also be formed of other materials, for example filter materials. It is also possible for the metal foil 3 to be embodied with through-holes, so that the exhaust gas flows in the flow direction 25 and is divided at the first front side 24 and mixed with each other inside the channel structure 4. The

  It is also shown here that the channel structure 4 and the molded metal foil 3 are not connected to each other over the entire extent 27 in the direction of the axis 19. Instead, the front portion 28 and the rear portion 29 where the brazed joint is generated are formed proximate to the front side 24.

  FIG. 3 is a schematic view of how the connection is manufactured between the channel structure 4 and the housing 2 according to the prior art. For this reason, a relatively large brazing area 11 is proposed in the direction of the circumference 6. The brazing region 11 may here be formed circumferentially and / or in the form of a patch. In any case, they have a considerable extent in the direction of the circumference 6.

  In contrast, FIG. 4 shows a variant of the embodiment of the honeycomb body 1 according to the invention. As can be seen from the opening shown in the upper right broken state, the honeycomb structure 4 is now formed with a plurality of smooth and corrugated metal foils 3. These metal foils 3 abut the inner side surface 12 of the housing 2 at their edges 8. A linear brazing connection 5 is then achieved precisely in this contact area 9 at the desired position by providing a corresponding brazing material 10. It is clear here that continuous brazing regions are not formed in the direction of the circumference 6 but rather are formed by accumulating linear brazing connections 5 spaced apart from one another. The width 7 of the linear connecting part 5 is here preferably less than 2 mm.

  5 to 10 show a preferable method for manufacturing such a honeycomb body 1. FIG. 5 shows a smooth metal foil 3 with edges 8 on both sides. FIG. 6 shows the application of adhesive 14 (eg, a binder). In this connection, the printer device 21 is moved across the metal foil 3 so that the adhesive strip 13 is formed close to a particular position, for example the edge 8. Note that in each case, the position of the adhesive strip 13 at the edge 8 does not have to be symmetrical, but rather a random pattern may be generated here.

  A plurality of such smooth metal foils 3 and further corrugated metal foils 3 (not shown in more detail here) may then be stacked and wound together so that a channel structure 4 is formed. . This channel structure 4 may then be introduced into a single piece housing 2, as shown as a cylinder in FIG. In this connection, the edge 8 of the metal foil 3 comes into contact with the inner side surface 12 of the housing 2.

  FIG. 8 shows that the front side 24 of the honeycomb body 1 manufactured in this way is immersed in, for example, the brazing material 10. The brazing material is, for example, in powder form and can then be transported to the inner region of the channel structure 4, in particular to the adhesive strip 13, by means of a specific jogging mechanism and / or carrier material (air). . The brazing material 10 is then deposited on the desired adhesive strip 13.

  The honeycomb body produced in this way is, for example, transported to a furnace 22 where it is subjected to a heat treatment. A linear brazed joint is formed in this manner (eg, FIG. 9).

  If desired, a coating method (shown in FIG. 10) may subsequently occur, during which the brazed honeycomb body 1 is then fed to the coating device 35. The honeycomb body 1 can in particular be coated with a so-called washcoat and / or catalyst.

  FIG. 11 shows a variation of the embodiment of corrugated metal foil 3, which can be arranged alternately with a smooth metal foil, for example as shown in FIG. The corrugated metal foil 3 now has a structure 20 that forms a channel in the channel extending direction 26 by periodic repetition of the raised and lowered portions 30 and 31. The corrugated metal foil also has attachments 18 that extend into the interior of the channel and cause partial exhaust flow deflection. Openings 32 are provided adjacent to these (launched) attachments 18 through which the exhaust gases are optionally flowed as indicated by the arrows corresponding to the direction of flow 25, for example. It can flow to the adjacent channel. Mixing of flow to the left and right as well as up and down is possible here.

  FIG. 12 shows an enlarged detail of a smooth metal foil 3 (eg in a bent state) in contact with the inner lateral surface of the housing (not shown). In this illustration, it is intended to schematically show a linear brazing connection 5 that is in direct contact with the edge 8 of the metal foil 3. In this connection, the linear brazing connection 5 is embodied, for example, with a width 7 of 1 mm to 2 mm and a length 34 in the range of 5 mm to 10 mm.

DESCRIPTION OF SYMBOLS 1 Honeycomb body 2 Housing 3 Metal foil 4 Channel structure 5 Linear brazing connection part 6 Circumference 7 Width 8 Edge 9 Contact area 10 Brazing material 11 Brazing area 12 Side surface 13 Adhesive piece 14 Adhesive 15 Exhaust gas treatment element 16 Exhaust system 17 Vehicle 18 Engine 19 Shaft 20 Structure 21 Printer device 22 Furnace 23 Channel 24 Front side 25 Flow direction 26 Channel extending direction 27 Spread 28 Front part 29 Rear part 30 Raised part 31 Lower part 32 Opening part 33 Attachment part 34 Length 35 coating device

Claims (10)

  A honeycomb body (1) having at least one housing (2) and a metal foil (3) forming a channel structure (4), the channel structure (4) comprising a plurality of linear brazed connections ( A honeycomb body (1) attached to the housing (2) by 5).   The honeycomb body (1) according to claim 1, wherein each of the linear brazing connections (5) is embodied with a width of at most 5 millimeters in the direction of the circumference (6) of the housing (2). ).   A plurality of said metal foils (3) are in contact with said housing (2) at at least one edge (8), and each of said metal foils (3) is at least one linear brazed connection The honeycomb body (1) according to claim 1 or 2, arranged so as to form a part (5).   The honeycomb body according to any one of claims 1 to 3, wherein the housing (2) has a brazing material (10) only in a contact area (9) in contact with the metal foil (3). (1).   The honeycomb body (1) according to any one of claims 1 to 4, wherein a continuous brazing area (11) on the circumference is not provided in the direction of the circumference (6) of the housing (2). 1).   A brazing region (11) on the circumference having a plurality of the linear brazing connections (5) spaced apart from each other and orthogonal to the direction of the circumference (6); The honeycomb body (1) according to any one of the preceding claims, provided in the direction of the circumference (6) of the housing (2).   A maximum of 10% of the surface area of the inner lateral surface (12) covered by the channel structure (4) of the housing (2) is embodied in the linear brazed connection (5). The honeycomb body (1) according to any one of claims 1 to 6. A method for producing a honeycomb body (1) having at least one housing (2) and a metal foil (3) forming a channel structure (4), said method comprising at least the following steps:
(A) providing a plurality of metal foils (3);
(B) arranging a plurality of adhesive pieces (13) on at least a part of the metal foil (3);
(C) The metal foil (3) is introduced into the housing (2) so that the channel structure (4) is formed and at least a part of the adhesive piece (13) is in contact with the housing (2). Process;
(D) brazing the honeycomb body (1) such that the brazing material (10) is disposed on the adhesive strip (13) on the housing (2);
(E) heating the honeycomb body (1) to form a plurality of linear brazed joints (5) between the metal foil (3) and the housing (2);
Including a method.   The method according to claim 8, wherein the housing (2) is provided without the use of an adhesive (14) and the brazing material (10).   Use of the honeycomb body (1) according to any one of claims 1 to 7 or claims 8 and 9 as exhaust gas treatment element (15) in an exhaust system (16) of a vehicle (17). Use of the honeycomb body (1) according to any one of the above.

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